Age and genesis of the Gangcha gold deposit, western Qinling orogen, China

The Gangcha gold deposit in Hezuo, Gansu, China, is a newly discovered medium‐scale (19 tons) epithermal deposit occurring within the western Qinling orogenic belt. The Daguanshan Formation, represented by metamorphosed volcanic–clastic rock suite, is the main ore‐bearing strata. Gold occurs mainly as submicroscopic inclusions in sulphides and quartz. The hydrothermal alteration is characterized by mid‐ to low‐temperature mineral assemblages such as pyrite, arsenopyrite, and fluorspar. We report results from Rb–Sr isotopic dating of pyrites in the main orebody, which yield an isochron age of 225.3 ± 3.4 to 229.9 ± 4.7 Ma suggesting that the mineral deposit formed during the middle Triassic within a collisional orogenic setting. The initial 87Sr/86Sr value of pyrite (0.710326 to 0.710349) is lower than that of the continental crust and higher than that of the mantle. The S isotope data of pyrites from the deposit show a narrow range from 0.6‰ to 1.3‰ with an average of 0.975‰. Their Pb isotopes exhibit characteristics of a crust–mantle mixed source with a μ (238U/204Pb) of 9.39 to 9.53 and a ω (232Th/204Pb) of 36.81 to 38.14. The S and Pb isotopic composition indicates that ore‐forming materials were derived from a magma sourced in the lower crust, which also incorporated mantle components.

[1]  Qingfei Wang,et al.  Gold mineralization in China: Metallogenic provinces, deposit types and tectonic framework , 2016 .

[2]  Yunpeng Dong,et al.  Tectonic architecture and multiple orogeny of the Qinling Orogenic Belt, Central China , 2016 .

[3]  Chengli Zhang,et al.  Granitoid magmatism in the Qinling orogen, central China and its bearing on orogenic evolution , 2015, Science China Earth Sciences.

[4]  E. Carranza,et al.  Geological characteristics and ore-forming process of the gold deposits in the western Qinling region, China , 2015 .

[5]  D. Groves,et al.  Province-scale commonalities of some world-class gold deposits: Implications for mineral exploration , 2015 .

[6]  Zhang De-xia.  Indosinian magmatism and tectonic setting of Xiahe-Hezuo area, western Qinling Mountains——implications from the Dewulu quartz diorite and Laodou quartz dioritic porphyry , 2015 .

[7]  M. Santosh,et al.  Triassic tectonics and mineral systems in the Qinling Orogen, central China , 2014 .

[8]  M. Santosh,et al.  The dilemma of the Jiaodong gold deposits: Are they unique? , 2014 .

[9]  Xu Don.  The Ore Control Factors of Gold Deposits and Prospecting Direction in West Qinling of Gansu Province , 2014 .

[10]  X. Xue.  Granitoid magmatism and tectonic evolution in northern edge of the Western Qinling terrane , 2014 .

[11]  M. Santosh,et al.  Metallogeny and craton destruction: Records from the North China Craton , 2014 .

[12]  Y. Miao.  A preliminary study of the Triassic large-scale mineralization in China and its geodynamic setting , 2012 .

[13]  Zhang Hongfei,et al.  Petrogenesis and tectonic implications of the Early Indosinian Meiwu Pluton in West Qinling,central China , 2012 .

[14]  Liu Shan-bao.  The major gold concentration areas in China and their resource potentials , 2012 .

[15]  Yunpeng Dong,et al.  Tectonic evolution of the Qinling orogen, China: Review and synthesis , 2011 .

[16]  Chen Yan.  Indosinian tectonic setting,magmatism and metallogenesis in Qinling Orogen,central China , 2010 .

[17]  Lu Zhao-hua.  Introduction to the Metallogenic Theory by Transmagmatic Fluids , 2009 .

[18]  L. Xin.  Indosinian movement and metallogenesis in Qinling orogenic belt , 2008 .

[19]  Wang Xiao-xia.  Origin and Tectonic Setting of the Early Mesozoic Granitoids in Qinling Orogenic Belt , 2008 .

[20]  Jun Chen,et al.  The Sr and Nd isotopic variations of the Chinese Loess Plateau during the past 7 Ma: Implications for the East Asian winter monsoon and source areas of loess , 2007 .

[21]  S. Bin.  Sedimentary Facies Analysis and Sedimentary Environment Reconstruction from Late Permian to Early Triassic of West Qinling Area , 2007 .

[22]  Liu Yong,et al.  Igneous Petrotectonic Assemblages and Tectonic Settings: A Discussion , 2007 .

[23]  Yang Gui-cai,et al.  Tectonic-Magmatic Evolution and Gold Mineralization in Yangshan Gold Belt,Gansu Province,China , 2006 .

[24]  Chen Yong-gan,et al.  GEOLOGICAL AND GEOCHEMICAL FEATURES AND ORIGIN OF ZHAISHANG GOLD DEPOSIT IN THE MINXIAN COUNTY,GANSU , 2006 .

[25]  Li Hui,et al.  Geochronology and Nd-Sr-Pb isotops of the bimodal volcanic rocks of the Bogda rift. , 2006 .

[26]  Jin Wei.  SHRIMP dating of adakites in western Qinling and their implications. , 2005 .

[27]  Yin Xian-ming.  POTENTIAL ANALYSIS AND PROSPECTIVE VALUE FOR GOLD RESOURCES OF WESTERN QINLING IN GANSU PROVINCE , 2004 .

[28]  Feng Jian-zhong.  Stable isotope geochemistry of three typical gold deposits in the West Qinling , 2004 .

[29]  Lu Yuanfa,et al.  GeoKit——A geochemical toolkit for Microsoft Excel , 2004 .

[30]  K. Ludwig.  User's Manual for Isoplot 3.00 - A Geochronological Toolkit for Microsoft Excel , 2003 .

[31]  S. Garwin,et al.  Geology, distribution, and classification of gold deposits in the western Qinling belt, central China , 2002 .

[32]  Sun Xing-li.  Isotopic Tracer of Material Origin for Hydrothermal Sedimentary Rocks and Significance in Xicheng Mineralization Area , 2002 .

[33]  Jin-Hui Yang,et al.  Rb-Sr, Sm-Nd, and Pb isotope systematics of pyrite: Implications for the age and genesis of lode gold deposits , 2001 .

[34]  Zhang Yao-dai.  THE RELATION BETWEEN ROCKBODY AND GOLD ORE DEPOSIT THE CHARACTERISTICS OF LIBA GOLD MINE , 2001 .

[35]  L. Tong.  GOLD DEPOSIT TYPES AND METALLOGENIC BELTS OF WEST QINLING AREA , 2000 .

[36]  Guowei Zhang,et al.  Timing of collision of the North and South China blocks: Controversy and reconciliation , 1999 .

[37]  Zhang Guowei,et al.  Indosinian Shahewan rapakivi granite in Qinling and its dynamic significance , 1996 .

[38]  Janick F Artiola,et al.  Using Geochemical Data: Evaluation, Presentation, Interpretation , 1994 .

[39]  E. Eide,et al.  40Ar/39Ar geochronology and exhumation of high-pressure to ultrahigh-pressure metamorphic rocks in east-central China , 1994 .

[40]  S. Hart,et al.  Collision of the North China and Yangtse Blocks and formation of coesite-bearing eclogites: Timing and processes☆ , 1993 .

[41]  G. Tilton,et al.  Timing of collision of the Sino-Korean and Yangtse cratons: U-Pb zircon dating of coesite-bearing eclogites , 1993 .

[42]  I. Wendt,et al.  The statistical distribution of the mean squared weighted deviation , 1992 .

[43]  J. Lorand,et al.  Sulphur isotope composition of orogenic spinel lherzolite massifs from Ariege (North-Eastern Pyrenees, France): An ion microprobe study , 1990 .

[44]  S. Hart,et al.  TIMING OF COLLISION BETWEEN THE NORTH AND SOUTH CHINA BLOCKS——THE Sm-Nd ISOTOPIC AGE EVIDENCE , 1989 .